1. Field of the Invention
The present invention relates to an organic EL display device capable of alternately displaying right and left parallax images to allow a person to view these images stereoscopically using shutter glasses, and a method of driving such an organic EL display device.
2. Description of the Related Art
Organic EL display devices including an array of a large number of pixel circuits each having a self light emitting organic electroluminescence (EL) element do not require a backlight and have no limitation in their viewing angle, and are therefore expected as a next-generation image display device.
An organic EL element is a current-driven light emitting element that controls its luminance based on an amount of current flow. Methods of driving the organic EL element include a passive matrix method and an active matrix method. With the passive matrix method, it is difficult to realize a large-sized and high-definition display, while the structure of pixel circuits can be simplified. Thus, there have been developed active matrix organic EL display devices including an array of pixel circuits each having a drive transistor for each organic EL element.
In recent years, methods of displaying a three-dimensional image (stereoscopic image) using such a display device have been studied. Among these, there is known a method of alternately displaying a right-eye parallax image and a left-eye parallax image, and opening and closing shutters of shutter glasses in synchronization with displaying of the right and left parallax images such that during a period in which the right-eye parallax image is displayed, a right-eye shutter is opened and a left-eye shutter is closed so as not to allow the right-eye parallax image to be viewed by left eye, and during a period in which the left-eye parallax image is displayed, the left-eye shutter is opened and the right-eye shutter is closed so as not to allow the left-eye parallax image to be viewed by right eye.
However, as an organic EL display device updates a displayed image by performing a line-sequential writing operation for each line, a time period for displaying each parallax image is limited, resulting in a problem of a significant reduction in luminance of the displayed image.
In order to prevent such luminance reduction, there is proposed an organic EL display device having pixel circuits each provided with a first storage capacity and a second storage capacity, where a line-sequential writing operation is performed to the first storage capacity while an image is displayed using the second storage capacity, the line-sequential writing operation is performed to the second storage capacity while an image is displayed using the first storage capacity after the writing operation to the first storage capacity is completed, and whereby the displayed image is updated (see International Publication No. WO2011/077718, for example).
According to the organic EL display device described in WO2011/077718, the most part of the driving time can be used for displaying images even when displaying three-dimensional images. However, this organic EL display device requires two large-area storage capacities for each pixel circuit, and therefore a proportion of a light-emitting region for each pixel circuit is reduced. This results in a problem that it is not possible to display an image with high luminance. In addition, even when displaying normal two-dimensional images (planar images), similarly it is not possible to display an image with high luminance.